Kinetics of Soybean Oil Hydrolysis on Niobium Catalysts

The catalytic hydrolysis of soybean oil was used as an alternative for the production of monoglycerides (MG) and diglycerides (DG). The reactions were conducted in a stainless-steel tubular reactor in the temperature range of 240–290 °C, on niobium phosphate (NBP) and niobium oxide (NBO) as catalysts. In the hydrolysis reactions at 270 °C, the maximum selectivities of the products of interest were obtained at 22 % MG and 48 % DG for the reaction with NBP, and 7 % MG and 33 % DG with NBO, for 59 % and 36 % of triglyceride conversion in 10 min, respectively. The proposed kinetic model presented a good fit of the theoretical model with the experimental data, showing that the previous hypotheses considered for the mechanism development are suitable for describing the kinetics of soybean oil hydrolysis.     

Evaluation of Transport Phenomena for Removing Vanadium from Petrochemical Industry Solid Waste

Transport phenomena are investigated which are involved in the electrokinetic remediation process used for removing vanadium from deactivated catalysts from oil catalytic cracking that are currently allotted to cement plants and class-I landfills. Variables such as the concentration of electrolyte, electric potential, and applied electric current were evaluated in order to determine the effects produced by electroosmosis, diffusion, hydraulic gradient, and electromigration on the removal of vanadium from the catalyst. It was observed that migration is the most relevant phenomenon in the remediation tests, and for the best remediation condition, the migratory flow accounted for about 87 % of the vanadium removal.     

Microbiological and biochemical changes in minimally processed fresh-cut Conference pears

Fresh-cut Conference pears were packaged under different modified atmosphere packaging (MAP) conditions and stored in refrigeration. The effects of packaging atmospheres on the microbial viability as well as on the changes in acidity, sugars and ascorbic acid (AA) were studied throughout storage. The use of plastic bags of a permeability of 15 cm ³ O ₂ m ^-2bar ^-1 24 h ^-1 and initial atmospheres of 0 kPa O ₂ extended the microbiological shelf life of pear cubes for at least 3 weeks of storage. Under these conditions, AA levels were kept almost unvaried throughout storage due to the restrictions in the O ₂ availability inside the bags' headspaces. However, these conditions also triggered physiological and biochemical changes that caused greater changes in the product acidity. The sugar profile was also affected by storage, but MAP did not show any significant influence on the reported changes.     

What is the source of ochratoxin A in wine?

During a microvinification trial using natural mouldy grapes from a research experimental vineyard, ochratoxin A (OTA) contaminated white wine was obtained. Potential OTA-producing mycobiota of grape samples used in this microvinification process was assessed. Only Aspergillus carbonarius isolates were detected as producers of OTA. Our report is a strong evidence of the contribution of A. carbonarius in the OTA contamination in wine.     

Determination of IgG levels in bovine bulk milk samples from different regions of Spain

Colostrum addition to milk for consumption is an unlawful practice. Furthermore, the higher whey protein/casein ratio of colostrum compared with milk causes severe technological problems. A high concentration of immunoglobulins has been generally accepted as an index of colostrum presence in milk. In this work, the levels of IgG have been determined by a non-competitive ELISA in 3,248 bulk bovine milk samples from different regions of Spain throughout one year. The mean value for IgG concentration obtained from all the samples was 0.257±0.122 mg/ml, within the range generally considered as acceptable for mature milk. The mean concentration obtained for all the samples collected in the spring was 0.288±0.125 mg/ml, significantly higher than the values found at the other seasons. The finding of some samples with very high values of IgG would suggest that the determination of immunoglobulin levels periodically would be a good parameter to control milk quality.     

Surface treatment of glass fiber and carbon fiber posts: SEM characterization

Morphology, etching patterns, surface modification, and characterization of 2 different fiber posts: Gfp, Glass fiber post; and Cfp, carbon fiber were investigated by SEM analysis, after different surface treatments. Thirty fiber posts, being 15 Gfp and 15 Cfp were divided into a 5 surface treatments (n = 3): C-alcohol 70% (control); HF 4%-immersion in 4% hydrofluoric acid for 1min; H(3) PO(4) 37%-immersion in 37% phosphoric acid for 30s; H(2) O(2) 10%-immersion in 10% hydrogen peroxide for 20 min; H(2) O(2) 24%-immersion in 24% hydrogen peroxide for 10 min. Morphology, etching patterns, surface modification and surface characterization were acessed by SEM analysis. SEM evaluation revealed that the post surface morphology was modified following all treatment when compared with a control group, for both type of reinforced posts. HF seems to penetrate around the fibers of Gfp and promoted surface alterations. The Cfp surface seems to be inert to treatment with HF 4%. Dissolution of epoxy resin and exposure of the superficial fiber was observed in both post groups, regardless the type of reinforcing fiber, H(2) O(2) in both concentrations. Relative smooth surface area was produced by H(3) PO(4) 37% treatment, but with similar features to untreated group. Surface treatment of fiber post is a determinant factor on micromechanical entanglement to resin composite core. Post treatment with hydrogen peroxide resulted strength of carbon and glass/epoxy resin fiber posts to resin composite core.